452 



AIlTintOPODA. 



organs and with tlie lj;isal maxillary process to comminute tlie 

 food. In the male the pedipaljii liave the terminal joint swollen 

 to a pear-shaped structure (fig. 4G0) by which the sexes are easily 



Fig. 468. 

 Fn;. 468. — Latrodfctefi niactrnifi 

 Fl(i, 469.- Pedipalp of Pardvsn 

 Fig. 470.— Spinnerets of Epei 



and third ypinnerety; /, threads 



Fig. 469. 

 + poison spider. (After ]\Iars.) 

 xincntii.. (After Enierton.) 

 dinilenia. (After "Warburton. 



second, 



distinguished. This is used to convey the spermatozoa to the 

 female, a rather dangerous process, as the male is apt to he killed 

 by the much stronger mate. 



At the hinder end of the abdomen, jitst in front of the anu.s, 

 are the spinnerets, which are reduced appendages, as is shown by 

 their jiaired arrangement and their jointing (fig. 4T0), as well as 

 by development. They are truncate and have at the tip a "spin- 

 ning field' from which numerous minute, two-jointed spinning 

 tubes, resembling hairs, arise, eiich of which is the end of a duet 

 of a silk gland. Different kinds of glands, prodttcing silk for differ- 

 ent purposes, occur. The number of spinnerets varies between two 

 and three pairs, and in front of these may be an unpaired spinning 

 region, the cribrellum, so that hundreds or even thousands (Epei- 

 ridae) of glands may be jiresent. 



Tlie secretion of the glands hanloiis in contact with the air, and tlie 

 single threads are united by the combs of the hinder feet into a larger eonl 

 which can be regulated in size according to the number of glands which 

 are active. Yet the largest cord is finer than the finest silkworm silk, 

 hence it is often used for the cross-hairs of telescopes. The siiider silk has 

 many uses; it is used to line the nests, to form cocoons for the eggs, as a 

 means of descent from higlv places, and to form the well-known wefis. 



The nervous system consists of a brain and a circumo'sophageal ring, 

 and, in the Mygalidas a single abdominal ganglion. The arrangement of 

 the six or eight ocelli and the relative lengths of the legs are matters of 

 systematic importance. Two pairs of respiratory organs occur. In the 

 Tetrapneumones there are two pair of lungs, but in the Dipneumones the 



